1. Field of the Invention
The present invention relates generally to the insertion of subcutaneous biosensors and, more specifically, to a device and method for implanting a biosensor at a selected site within the body of a patient.
2. Discussion of Related Art
Biosensors have been increasingly used to monitor physical characteristics of human and animal subjects. Such biosensors can be placed underneath the skin of a subject and used to measure, for example, blood glucose levels. An example of such a biosensor can be found in U.S. Pat. No. 6,330,464, the disclosure of which is incorporated herein by reference. There, an optical-based biosensor is disclosed which is capable of detecting the presence or amount of analyte in blood. Of course, such biosensors must be compatible with human and animal tissue and must maintain their integrity within moisture-rich environments. Oftentimes, the exterior of the biosensors are made of materials sensitive to the drying effects of air and must be constantly hydrated in order to maintain device integrity. For example, U.S. Pat. No. 6,330,464 discloses optical based sensors with fluorescent indicator molecules distributed throughout a matrix layer coated on the exterior surface of the sensor body. Of course, the biosensors must also be kept sterilized prior to insertion into the subject in order to avoid infection.
Certain insertion devices are known in the art for implanting sensors subcutaneously into subjects. For example, U.S. Pat. No. 4,787,384 discloses a system and device for implanting a solid identification marker underneath the animal's skin that allows scientists to mark a given animal for tracking or testing purposes. However, this system has several disadvantages. First, the system contains at least one projection extending into the hollow tube that is configured to trap the marker in place by friction fitting. Such a projection could damage the coating of a biosensor, especially in the case where the exterior surface of the biosensor is coated with an indicator chemistry and the like. Also, the disclosure of U.S. Pat. No. 4,787,384 does not teach or suggest providing for consistent hydration of the marker for the period prior to insertion. Accordingly, the disclosure provides no means of hydrating a biosensor.
Insertion devices for implanting sensors are also described in, among others, U.S. Pat. Nos. 6,936,006, 5,074,318 and 5,002,548.
What is desired, therefore, is a system and method to overcome at least some of the disadvantages of the prior art and to effectively store and insert sterilized biosensors into subjects while preserving biosensor integrity.